K-Patents SeedMaster 2 - Manual (Page 17)

3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER … 17
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1. supersaturation (-)
2. crystal content (% by volume)
3. mother liquor purity (%)
4. massecuite density (kg / m)
5. massecuite solids content (%)
6. massecuite consistency (%)
7. mean crystal size (mm)
Parameters No.1. and No.2. are the important ones for the advanced control of crystallization.
Parameters No.1. … No.3. and No.7. represent a drastic change in the type of information available in
real time for crystallization control, while No.4….No.6 provide accustomed data.
NOTES:
1. Any 2 out of the 7 (per crystallizer) listed above can be selected for transmission by standard (0…20 mA,
or 4…20 mA) current output.
2. All of these and some other data can be transmitted to a PC (Personal Computer), or PCS (Process
Control System) via digital communication.
3. Mean crystal size data are approximate and valid only if full seeding is practiced and no dissolution
of crystals or further nucleation takes place during crystallization.
3.5 On-line data inputs
The 2 obligatory on-line (real-time) data inputs required for the correct operation of SeedMaster 2 are:
1. syrup / mother liquor concentration, and
2. massecuite temperature.
It is highly recommended to use a third on-line data input (“Third input”) as well, which can be selected
from those listed below:
3. massecuite density (kg / m), or
massecuite solids content (%), or
stirrer motor power consumption (kW), or
stirrer motor current (A).
It does not matter what kind of instrument (nuclear, microwave etc.) is being used to measure density, or
solids content. If stirrer motor consumption provides the 3
rd data input, power consumption (kW) data are
preferred.
3.5.1 Receiving syrup concentration data from the K-PATENTS refractometer(s)
There are several ways to transmit concentration data originating from a K-PATENTS refractometer to
SeedMaster 2 (see Ch. 7.2):
1. Standard current transmission (4 – 20 mA).
The transmitter can be the refractometer itself, or the standard current may come as current output from a
DCS-, or PLC-based Process Control System (PCS) already receiving the data from the refractometer. In this
case an analogue input channel of SeedMaster 2 should be used.
2. Digital communication using ports COM1, COM2, or COM3.
It is possible to transmit concentration (and temperature) data measured by K-PATENTS PR-01-S type
refractometer(s) by using serial data communication (RS232, RS422, RS485). SeedMaster 2 has 3 serial
ports (COM1, COM2, COM3). Two of these can be used to receive data directly from 2 PR-01-S type
refractometers at the same time . Cable length should be short, not exceeding 15 meters.
3. All data exchange (inputs and outputs) between SeedMaster 2 and a PCS can be implemented by
using one of the COM1…COM3 ports and MODBUS SLAVE (ASCII RTU) protocol.
4. Data input (concentration and temperature) to SeedMaster 2 from a K-PATENTS PR-23 type
refractometer with 1 or 2 sensor heads can be implemented by directly connecting them using the standard
ETHERNET connection and UDP / IP K-PATENTS refractometer protocol.
5. All data exchange (inputs and outputs) between SeedMaster 2 and a PCS can be implemented by
using the standard ETHERNET connection and TCP / IP MODBUS TCP protocol.
3.5.2 Receiving temperature data
Massecuite temperature is always measured by the sensor probe of the K-PATENTS refractometer and may
be available for transmission as standard current (4 – 20 mA) output (option). The Indicating Transmitter of